Methods and devices for attaching connective tissues to bone using a knotless suture anchoring device

ABSTRACT

A device for attaching connective tissue to bone has a longitudinal axis and comprises an annular toggle member and a body member disposed distally of the toggle member, such that there is an axial space between the toggle member and the body member. The toggle member is movable between an undeployed position wherein the toggle member has a smaller profile in a direction transverse to the axis and a deployed position wherein the toggle member has a larger profile in the direction transverse to the axis. When installed in a desired procedural site, in suitable bone, suturing material extends axially through a center aperture in the annular toggle member, without being secured to or contacting the toggle member. This approach permits a suture attachment which lies entirely beneath the cortical bone surface, and which further permit the attachment of suture to the bone anchor without the necessity for tying knots, which is particularly arduous and technically demanding in the case of arthroscopic procedures.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 10/879,669filed Jun. 29, 2004, now U.S. Pat. No. 7,556,640, which is acontinuation of application Ser. No. 09/876,488 filed Jun. 7, 2001, nowU.S. Pat. No. 6,770,076, which claims the benefit under 35 U.S.C. 119(e)of Provisional Application Ser. No. 60/273,137, filed on Mar. 2, 2001.application Ser. No. 09/876,488 filed Jun. 7, 2001, is also acontinuation-in-part of application Ser. No. 09/781,793, filed on Feb.12, 2001, now U.S. Pat. No. 7,083,638, expressly incorporated byreference herein, and commonly assigned herewith.

BACKGROUND OF THE INVENTION

This invention relates generally to methods and apparatus for attachingsoft tissue to bone, and more particularly to anchors and methods forsecuring connective tissue, such as ligaments or tendons, to bone. Theinvention has particular application to arthroscopic surgical techniquesfor reattaching the rotator cuff to the humeral head, in order to repairthe rotator cuff.

It is an increasingly common problem for tendons and other soft,connective tissues to tear or to detach from associated bone. One suchtype of tear or detachment is a “rotator cuff” tear, wherein thesupraspinatus tendon separates from the humerus, causing pain and lossof ability to elevate and externally rotate the arm. Complete separationcan occur if the shoulder is subjected to gross trauma, but typically,the tear begins as a small lesion, especially in older patients.

To repair a torn rotator cuff, the typical course today is to do sosurgically, through a large incision. This approach is presently takenin almost 99% of rotator cuff repair cases. There are two types of opensurgical approaches for repair of the rotator cuff, one known as the“classic open” and the other as the “mini-open”. The classic openapproach requires a large incision and complete detachment of thedeltoid muscle from the acromion to facilitate exposure. The cuff isdebrided to ensure suture attachment to viable tissue and to create areasonable edge approximation. In addition, the humeral head is abradedor notched at the proposed soft tissue to bone reattachment point, ashealing is enhanced on a raw bone surface. A series of small diameterholes, referred to as “transosseous tunnels”, are “punched” through thebone laterally from the abraded or notched surface to a point on theoutside surface of the greater tuberosity, commonly a distance of 2 to 3cm. Finally, the cuff is sutured and secured to the bone by pulling thesuture ends through the transosseous tunnels and tying them togetherusing the bone between two successive tunnels as a bridge, after whichthe deltoid muscle must be surgically reattached to the acromion.Because of this maneuver, the deltoid requires postoperative protection,thus retarding rehabilitation and possibly resulting in residualweakness. Complete rehabilitation takes approximately 9 to 12 months.

The mini-open technique, which represents the current growing trend andthe majority of all surgical repair procedures, differs from the classicapproach by gaining access through a smaller incision and splittingrather than detaching the deltoid. Additionally, this procedure istypically performed in conjunction with arthroscopic acromialdecompression. Once the deltoid is split, it is retracted to expose therotator cuff tear. As before, the cuff is debrided, the humeral head isabraded, and the so-called “transosseous tunnels”, are “punched” throughthe bone or suture anchors are inserted. Following the suturing of therotator cuff to the humeral head, the split deltoid is surgicallyrepaired.

Although the above described surgical techniques are the currentstandard of care for rotator cuff repair, they are associated with agreat deal of patient discomfort and a lengthy recovery time, rangingfrom at least four months to one year or more. It is the above describedmanipulation of the deltoid muscle together with the large skin incisionthat causes the majority of patient discomfort and an increased recoverytime.

Less invasive arthroscopic techniques are beginning to be developed inan effort to address the shortcomings of open surgical repair. Workingthrough small trocar portals that minimize disruption of the deltoidmuscle, a few surgeons have been able to reattach the rotator cuff usingvarious bone anchor and suture configurations. The rotator cuff issutured intracorporeally and an anchor is driven into bone at a locationappropriate for repair. Rather than thread the suture throughtransosseous tunnels which are difficult or impossible to createarthroscopically using current techniques, the repair is completed bytying the cuff down against bone using the anchor and suture. Earlyresults of less invasive techniques are encouraging, with a substantialreduction in both patient recovery time and discomfort.

Unfortunately, the skill level required to facilitate an entirelyarthroscopic repair of the rotator cuff is inordinately high.Intracorporeal suturing is clumsy and time consuming, and only thesimplest stitch patterns can be utilized. Extracorporeal knot tying issomewhat less difficult, but the tightness of the knots is difficult tojudge, and the tension cannot later be adjusted. Also, because of theuse of bone anchors to provide a suture fixation point in the bone, theknots that secure the soft tissues to the anchor by necessity leave theknot bundle on top of the soft tissues. In the case of rotator cuffrepair, this means that the knot bundle is left in the shoulder capsulewhere it can be felt by the patient postoperatively when the patientexercises the shoulder joint. So, knots tied arthroscopically aredifficult to achieve, impossible to adjust, and are located in less thanoptimal areas of the shoulder. Suture tension is also impossible tomeasure and adjust once the knot has been fixed. Consequently, becauseof the technical difficulty of the procedure, presently less than 1% ofall rotator cuff procedures is of the arthroscopic type, and isconsidered investigational in nature.

Another significant difficulty with current arthroscopic rotator cuffrepair techniques is shortcomings related to currently available sutureanchors. Suture eyelets in bone anchors available today, which like theeye of a needle are threaded with the thread or suture, are small inradius, and can cause the suture to fail at the eyelet when the anchoris placed under high tensile loads.

There are various bone anchor designs available for use by an orthopedicsurgeon for attachment of soft tissues to bone. The basic commonalitybetween the designs is that they create an attachment point in the bonefor a suture that may then be passed through the soft tissues and tied,thereby immobilizing the soft tissue. This attachment point may beaccomplished by different means. Screws are known for creating suchattachments, but existing designs suffer from a number of disadvantages,including their tendency to loosen over time, requiring a secondprocedure to later remove them, and their requirement for a relativelyflat attachment geometry.

Another approach is to utilize the difference in density in the corticalbone (the tough, dense outer layer of bone) and the cancellous bone (theless dense, airy and somewhat vascular interior of the bone). There is aclear demarcation between the cortical bone and cancellous bone, wherethe cortical bone presents a kind of hard shell over the less densecancellous bone. The aspect ratio of the anchor is such that ittypically has a longer axis and a shorter axis and usually ispre-threaded with a suture. These designs use a hole in the corticalbone through which an anchor is inserted.

The hole is drilled such that the shorter axis of the anchor will fitthrough the diameter of the hole, with the longer axis of the anchorbeing parallel to the axis of the drilled hole. After deployment in tothe cancellous bone, the anchor is rotated 90^(B) so that the long axisis aligned perpendicularly to the axis of the hole. The suture ispulled, and the anchor is seated up against the inside surface of thecortical layer of bone. Due to the mismatch in the dimensions of thelong axis of the anchor and the hole diameter, the anchor cannot beretracted proximally from the hole, thus providing resistance topull-out. These anchors still suffer from the aforementioned problem ofeyelet design that stresses the sutures.

Still other prior art approaches have attempted to use a “pop rivet”approach. This type of design requires a hole in the cortical bone intowhich a split shaft is inserted. The split shaft is hollow, and has atapered plug leading into its inner lumen. The tapered plug is extendedout through the top of the shaft, and when the plug is retracted intothe inner lumen, the tapered portion causes the split shaft to be flaredoutwardly, ostensibly locking the device into the bone.

Other methods of securing soft tissue to bone are known in the priorart, but are not presently considered to be feasible for shoulder repairprocedures, because of physicians' reluctance to leave anything but asuture in the capsule area of the shoulder. The reason for this is thatstaples, tacks, and the like could possibly fall out and cause injuryduring movement. As a result of this constraint, the attachment pointoften must be located at a less than ideal position. Also, the tacks orstaples require a substantial hole in the soft tissue, and make itdifficult for the surgeon to precisely locate the soft tissue relativeto the bone.

As previously discussed, any of the anchor points for sutures mentionedabove require that a length of suture be passed through an eyeletfashioned in the anchor and then looped through the soft tissues andtied down to complete the securement. Much skill is required, however,to both place the sutures in the soft tissues, and to tie knots whileworking through a trocar under endoscopic visualization.

There have been attempts to solve some of the problems that exist incurrent anchor designs. One such approach is disclosed in U.S. Pat. No.5,324,308 to Pierce. In this patent, there is disclosed a suture anchorthat incorporates a proximal and distal wedge component having inclinedmating faces. The distal wedge component has two suture thread holes atits base through which a length of suture may be threaded. The assemblymay be placed in a drilled hole in the bone, and when tension is placedon the suture, the distal wedge block is caused to ride up against theproximal wedge block, expanding the projected area within the drilledhole, and locking the anchor into the bone. This approach is a usefulmethod for creating an anchor point for the suture, but does not in anyway address the problem of tying knots in the suture to fix the softtissue to the bone.

The problem of placing sutures in soft tissues and tying knots in anendoscopic environment is well known, and there have been attempts toaddress the problem and to simplify the process of suture fixation. Onesuch approach is disclosed in U.S. Pat. No. 5,383,905 to Golds et al.The patent describes a device for securing a suture loop about bodilytissue that includes a bead member having a longitudinal bore and ananchor member adapted to be slidably inserted within the bore of thebead member. The anchor member includes at least two axial compressiblesections which define a passageway to receive two end portions of asuture loop. The axial sections collapse radially inwardly uponinsertion of the anchor member within the bore of the bead member tosecurely wedge the suture end portions received within the passageway.

Although the Golds et al. patent approach utilizes a wedge-shaped memberto lock the sutures in place, the suture legs are passing through thebore of the bead only one time, in a proximal to distal direction, andare locked by the collapsing of the wedge, which creates an interferenceon the longitudinal bore of the anchor member. Also, no provision ismade in this design for attachment of sutures to bone. The design isprimarily suited for locking a suture loop, such as is used for ligationor approximation of soft tissues.

A prior art approach that includes tissue attachment is described inU.S. Pat. No. 5,405,359 to Pierce. In this system, a toggle wedge iscomprised of a two piece structure comprising a top portioncharacterized by the presence of a barbed tip and a bottom portion. Thesuturing material extends through apertures in each of the two toggleportions, and is maintained in position by means of a knot disposed inthe suture at a lower edge of the bottom toggle portion. To anchor thesuture into adjacent soft tissue, the two toggle portions are rotatedrelative to one another, as shown for example in FIG. 33. The disclosurestates that the device could be used to anchor suture in bone, as wellas soft tissue, if two embodiments are utilized in tandem. However, thesystem is disadvantageous in that it is complex, difficult tomanipulate, and still requires the tying of a knot in the suture.

Another approach that includes bone attachment is described in U.S. Pat.No. 5,584,835 to Greenfield. In this patent, a two part device forattaching soft tissue to bone is shown. A bone anchor portion is screwedinto a hole in the bone, and is disposed to accept a plug that has beenadapted to receive sutures. In one embodiment, the suture plug isconfigured so that when it is forced into its receptacle in the boneanchor portion, sutures that have been passed through an eyelet in theplug are trapped by friction between the wall of the anchor portion andthe body of the plug portion.

Although there is some merit to this approach for eliminating the needfor knots in the attachment of sutures to bone, a problem with beingable to properly set the tension in the sutures exists. The user isrequired to pull on the sutures until appropriate tension is achieved,and then to set the plug portion into the bone anchor portion. Thisaction increases the tension in the sutures, and may garrot the softtissues or increase the tension in the sutures beyond the tensilestrength of the material, breaking the sutures. In addition, the minimalsurface area provided by this anchor design for pinching or locking thesutures in place will abrade or damage the suture such that the suture'sability to resist load will be greatly compromised.

A disclosure that incorporates bone attachment and eliminates knot tyingis set forth in U.S. Pat. No. 5,702,397 to Goble et al. One embodiment,in particular, is shown in FIG. 23 of that patent and includes a boneanchor that has a threaded body with an inner cavity. The cavity is opento one end of the threaded body, and joins two lumens that run out tothe other end of the threaded body. Within the cavity is disposed agear, journaled on an axle. A length of suture is threaded through onelumen, around the gear, and out through the other lumen. A ball isdisposed within the cavity to ride against a tapered race and ostensiblylock the suture in place. What is not clear from the patent disclosureis how the force D shown as the tension in the suture would lock theball into the race. Although this embodiment purports to be aself-locking anchor adapted for use in blind holes for fixing suturesinto bone, the construct shown is complicated, and does not appear to beadequate to reliably fixate the suture.

U.S. Pat. No. 5,782,863 to Bartlett discloses a suture anchor includingbone attachment, which simply comprises a conical suture anchor havingan anchor bore through which a length of suture is threaded. The anchoris inserted into a bore within a portion of bone using an insertion toolhaving a shape memory insertion end. As the anchor is inserted, becauseof its conical shape, it will re-orient itself by rotating in order tofit into the bore, bending the end of the insertion tool. However, oncethe proximal edge of the bone anchor enters cancellous bone, the shapememory insertion end of the insertion tool will begin resuming itsnatural straight orientation, thus rotating the anchor back into itsoriginal orientation. The corners of the conical body thus protrude intothe soft cancellous bone, and the anchor body is prevented from exitingproximally from the bone bore through the hard cortical bone. Theinsertion tool is then removed.

The Bartlett patent approach, while innovative, is disadvantageous tothe extent that it involves the use of a unique and complex insertiontool, and can be difficult to deploy. It also does not permit suturingof the soft tissue prior to anchoring the suture to bone, and thus doesnot permit tensioning of the suture to approximate the soft tissue tobone, as desired, at the conclusion of the suturing procedure.Additionally, in preferred embodiments, the suture is knotted to theanchor, a known disadvantage.

Yet another prior art approach is disclosed in U.S. Pat. No. 5,961,538to Pedlick et al. In this patent, a wedge shaped suture anchor system isdescribed for anchoring a length of suture within a bore in a boneportion, which comprises an anchor body having an offset suture openingfor receiving the length of suture therethrough, and for creating animbalance in the rotation of the device as it is inserted. A shaftportion is utilized to insert the wedge-shaped anchor body into the bonebore. Once the anchor body is in cancellous bone, below the corticalbone layer, the shaft is pulled proximally to cause the anchor body torotate, thereby engaging the corners of the anchor body with thecancellous bone. The shaft then becomes separated from the anchor body,leaving the anchor body in place within the bone.

The Pedlick et al. approach is conventional, in that the suture isattached to desired soft tissue after it is anchored within the bone.Consequently, there is no opportunity to tension the suture, as desired,to optimally approximate the soft tissue to the bone upon completion ofthe surgical procedure. Additionally, the approach is complex andlimited in flexibility, since the suture is directly engaged with thebone anchoring body. There is also the possibility that the boneanchoring body will not sufficiently rotate to firmly become engagedwith the cancellous bone before the insertion tool breaks away from theanchor body, in which case it will be impossible to properly anchor thesuture.

U.S. Pat. No. 6,056,773 to Bonutti discloses a suture anchoring systemwhich is somewhat similar to that disclosed by Pedlick et al. Acylindrical suture anchor body is provided which is insertable into abone bore, using a pusher member which pushes distally on the anchorbody from a proximal direction. As the anchor body proceeds into thebone bore, below the cortical bone surface, the suture extending throughthe lumen of the anchor body applies a proximal tensile force on theanchor body, to cause the anchor body to rotate relative to the pushermember, thereby anchoring the anchor body in cancellous bone. Of course,this system has similar disadvantages to those of the Pedlick et al.system, and requires the suture to be directly engaged with the boneanchoring body.

What is needed, therefore, is a new approach for repairing the rotatorcuff or fixing other soft tissues to bone, wherein both the bone andsuture anchors reside completely below the cortical bone surface, thereis no requirement for the surgeon to tie a knot to attach the suture tothe bone anchor, and wherein suture tension can be adjusted and possiblymeasured. The procedure associated with the new approach should betterfor the patient than existing procedures, should save time, beuncomplicated to use, and be easily taught to practitioners having skillin the art.

SUMMARY OF THE INVENTION

The present invention solves the problems outlined above by providinginnovative bone anchor and connective techniques which permit a sutureattachment which lies entirely beneath the cortical bone surface, andwhich further permit the attachment of suture to the bone anchor withoutthe necessity for tying knots, which is particularly arduous andtechnically demanding in the case of arthroscopic procedures.

More particularly, in one aspect of the invention, a bone anchor deviceis provided for attaching connective tissue to bone, which has alongitudinal axis and comprises a toggle member and a preferably tubularbody member disposed distally of the toggle member. An axial space ispresent between the toggle member and the body member. A connectingportion is disposed in the axial space, which joins the toggle member tothe body member.

In operation, when it is desired to deploy the inventive bone anchordevice, the toggle member is movable, in a pivoting or rotationalfashion, between an undeployed position wherein the toggle member has asmaller profile in a direction transverse to the longitudinal axis,which is no wider than the transverse dimension or width of the bodymember and the hole into which the bone anchor device is disposed, and adeployed position wherein the toggle member has a larger profile in thedirection transverse to the axis, which is substantially larger than thewidth of the hole, so that the outer edges of the toggle member becomeembedded in the cancellous bone which lies beneath the cortical bonesurface, and so that there is no reasonable way, short of widening thehole through the cortical bone, of withdrawing the anchor proximally outof the hole.

When the toggle member is deployed, the connecting portion deforms suchthat the axial space is reduced in length.

The connecting portion preferably comprises a one or more struts havingproximal ends joined to the toggle member and distal ends joined to thebody member. In manufacture, the body member, struts, and toggle member,which is preferably annular and elliptical in configuration, may all befabricated from a single piece, such as a hypotube.

Preferably, the inventive toggle member is disposed at an acute anglerelative to the axis in the undeployed position, and is disposed in asubstantially transverse orientation relative to the axis in thedeployed position.

The inventors have discovered that, due to potential cyclic loadingeffects during usage of the affected body part after completion of themedical procedure, it is advantageous to form at least the connectingportion, and preferably the toggle member as well of a biocompatiblerelatively ductile material. In a presently preferred embodiment, thematerial comprises an annealed metal, such as stainless steel.

In a preferred embodiment, there is disposed a mandrel proximally of thetoggle member, and a casing extending through the toggle member. Themandrel, together with the body, is useful in actuating the togglemember from its undeployed position to its deployed position.

In another aspect of the invention, there is provided a bone anchordevice for attaching soft tissue to bone, which device has alongitudinal axis and comprises a toggle member being rotatable from anundeployed position wherein the toggle member has a smaller profile in adirection transverse to the axis and a deployed position wherein thetoggle member has a larger profile in the direction transverse to theaxis. The toggle member has no structure for attaching suture materialthereto, since the suture material is to be attached to a body memberdisposed distally of the toggle member.

In yet another aspect of the invention, there is provided an apparatusfor attaching connective tissue to bone, which apparatus has alongitudinal axis and comprises an annular toggle member and a bodymember disposed distally of the toggle member, such that there is anaxial space between the toggle member and the body member.Advantageously, the toggle member is movable between an undeployedposition wherein the toggle member has a smaller profile in a directiontransverse to the axis and a deployed position wherein the toggle memberhas a larger profile in the direction transverse to the axis. Wheninstalled in a desired procedural site, in suitable bone, suturingmaterial extends axially through a center aperture in the annular togglemember, without being secured to or contacting the toggle member.

In still another aspect of the invention, there is provided an apparatusfor attaching connective tissue to bone, which apparatus has alongitudinal axis and comprises a toggle member and a body memberdisposed distally of the toggle member, such that there is an axialspace between the toggle member and the body member. The toggle memberis movable between an undeployed position wherein the toggle member hasa smaller profile in a direction transverse to the axis and a deployedposition wherein the toggle member has a larger profile in the directiontransverse to the axis. A connecting portion is disposed in the axialspace and joins the toggle member to the body member.

In another aspect of the invention, there is provided an apparatus forattaching connective tissue to bone, which comprises an anchor bodyhaving a longitudinal axis and having an anchoring structure for fixingthe anchor body within a body cavity. The anchor body has a proximalend, a distal end, and a lumen opening at the proximal end, and furtherincludes a suture return member disposed therein such that a length ofsuture may be introduced into the lumen from the proximal end, loopedaround the suture return member, and passed out of the lumen through theproximal end. A suture locking plug is movable within the lumen from afirst position to a second position, and a bone anchoring member isattached to the anchor body, preferably at the proximal end thereof, andis movable between an undeployed position and a deployed position. Inpreferred embodiments of the invention, the suture return membercomprises a shaft or pin which may be either fixed or rotatable. Thebone anchoring member preferably comprises a toggle member, which, inthe undeployed position has a smaller profile in a direction transverseto the longitudinal axis and in the deployed position has a largerprofile in the direction transverse to the axis.

As noted supra, the toggle member is preferably disposed proximally ofthe anchor body such that there is an axial space between the togglemember and the anchor body. When the toggle member is moved from theaforementioned undeployed position to the aforementioned deployedposition, the axial space is reduced in length. A connecting portion isdisposed in the axial space and joins the toggle member to the anchorbody. The connecting portion preferably comprises a pair of strutshaving proximal ends joined to the toggle member and distal ends joinedto the anchor body.

In still another aspect of the invention, there is disclosed a method ofusing suture to secure soft tissue, preferably a tendon, with respect toa body cavity, preferably disposed in a portion of bone. The methodcomprises the steps of passing a length of suture material through softtissue so that a loop of suture material is disposed in the soft tissue,resulting in two free ends, and providing an anchor body having an openproximal end and a lumen. A suture return member is disposed in theanchor body. Additional steps include passing the two free ends of thelength of suture into the lumen of the anchor body through the openproximal end, and looping them about the suture return member such thatthe two free ends of the suture extend proximally from the lumen throughthe open proximal end. The anchor body is fixed with respect to the bodycavity, and the loop of suture material is tensioned by pulling on oneor both of the two free ends of the length of suture, to approximate thesoft tissue with respect to the body cavity as desired. A further stepis to fasten the two free ends of the length of suture with respect tothe anchor body without knots.

In preferred approaches, the step of fixing the anchor body with respectto the body cavity comprises forming the body cavity, passing the anchorbody into the body cavity, and radially expanding anchoring structure,preferably a deployable toggle member, on the anchor body. The anchoringstructure is provided on a proximal end of the anchor body so as toengage the cortical layer of the bone and to prevent proximal removal ofthe anchor body from the body cavity.

In yet another aspect of the invention, there is disclosed a method ofsecuring soft tissue to bone, comprising disposing an anchor body havinga longitudinal axis and having a length of suture secured therein withina bore disposed in a portion of bone, and deploying a toggle memberattached to a proximal end of the anchor body from an undeployedposition wherein the toggle member has a smaller profile in a directiontransverse to the axis to a deployed position wherein the toggle memberhas a larger profile transverse to the axis. The toggle member fixes theanchor body axially relative to the portion of bone. A connectingportion joins the toggle member to the anchor body, and is disposed inan axial space between the toggle member and the anchor body. Theaforementioned deploying step includes deforming the connecting portionas the toggle member is moved from the undeployed position to thedeployed position.

The invention, together with additional features and advantages thereof,may best be understood by reference to the following description takenin conjunction with the accompanying illustrative drawing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a first preferred embodiment of a boneanchor device constructed in accordance with the principles of thepresent invention;

FIG. 2 a is a schematic plan view of the embodiment of FIG. 1, in itsundeployed configuration;

FIG. 2 b is a schematic plan view similar to FIG. 2 a, showing theembodiment of FIG. 1 in its deployed configuration;

FIG. 3 is a perspective view of the bone anchor of FIG. 1, together withadditional structure which is employed during installation of the boneanchor in a desired bone site;

FIG. 4 is schematic cross-sectional view of a typical procedural site,in a human shoulder, for which the present invention may be employed;

FIG. 5 is a plan view, partially in cross-section, of the embodimentillustrated in FIG. 3, wherein the anchor is in its undeployedconfiguration;

FIG. 6 is a plan view similar to FIG. 5, showing the anchor after it hasbeen deployed;

FIG. 7 is a cross-sectional view of a typical procedural site,illustrating a preferred method for closing the inventive repairprocedure after the anchor has been deployed in a suitable bone site;

FIG. 8 is a schematic plan view of an alternative embodiment of theinventive bone anchor;

FIG. 9 a is a perspective view of another alternative embodiment of theinventive bone anchor;

FIG. 9 b is a perspective view, similar to FIG. 9 a, of yet anotheralternative embodiment of the inventive bone anchor;

FIG. 9 c is a perspective view, similar to those of FIGS. 9 a and 9 b,of still another alternative embodiment of the inventive bone anchor;

FIG. 10A is a partial sectional view through the left shoulder of ahuman as seen from the front showing the use of a minimally invasivesoft tissue to bone attachment system according to a presently preferredembodiment of the present invention;

FIG. 10B is an enlarged sectional view taken within the circle denoted10B in FIG. 10A;

FIGS. 11A-11D are enlarged sectional views of the use of the soft tissueto bone attachment system of FIG. 10A to reattach a rotator cuff tendon;

FIGS. 12A-12C are partial longitudinal sectional views through a distalend of an exemplary soft tissue to bone attachment system of the presentinvention;

FIG. 13A is a perspective view of a combined suture locking portion andbone anchor structure of the soft tissue to bone attachment system ofthe present invention, showing a locking plug disengaged from an anchorbody;

FIG. 13B is a partial longitudinal sectional view of the combined suturelocking portion and bone anchor structure taken along line 13B-13B ofFIG. 13A;

FIG. 13C is an end elevational view of the combined suture lockingportion and bone anchor structure taken along line 13C-13C of FIG. 13B;

FIG. 14 is a perspective view of an anchor body of the combined suturelocking portion and bone anchor structure of FIG. 13A;

FIG. 15 is a top plan view of the combined suture locking portion andbone anchor structure without the locking plug and an attached actuationrod;

FIG. 16A is a perspective view of an exemplary suture locking portion ofthe soft tissue to bone attachment system of the present inventionshowing a locking plug disengaged from an anchor body;

FIG. 16B is a partial longitudinal sectional view of the suture lockingportion taken along line 16B-16B of FIG. 16A;

FIG. 16C is an end elevational view of the suture locking portion takenalong line 16C-16C of FIG. 16A;

FIG. 17A is a perspective view of the exemplary suture locking portionof the soft tissue to bone attachment system of the present inventionshowing the locking plug engaged with the anchor body;

FIG. 17B is a partial longitudinal sectional view taken along line17B-17B of FIG. 17A;

FIG. 17C is an end elevational view taken along line 17C-17C of FIG. 17Aillustrating the locking plug clamping a length of suture against aninner lumen of the anchor body;

FIG. 18A is a side elevational view of the deployed anchor structurerelative to the anchor body and locking plug therein;

FIG. 18B is an end elevational view of FIG. 18A;

FIG. 19 is a partial sectional view through the left humeral head of ahuman as seen from the front showing the use of an alternative minimallyinvasive soft tissue to bone attachment system of the present invention;

FIG. 20A is a perspective view of a combined suture locking portion andbone anchor structure of the present invention, showing an alternativesuture pulley structure; and

FIG. 20B is a cross-sectional view taken along lines 20B-20B of FIG.20A.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now more particularly to the drawings, there is shown in FIG.1 a bone anchor 10, constructed in accordance with one embodiment of thepresent invention, in its undeployed state. The bone anchor 10 ispreferably comprised of a tubular or cylindrical body 12, which may, forexample, be a hypotube, in which a series of diagonal cuts have beenmade at its proximal end 13 to create an annular generally ellipticalangled toggle ring member 14. The cuts may be made by using wireElectro-Discharge Machining (EDM) techniques, though many other suitableknown methods and materials for fabricating a generally tubular body andassociated proximal toggle ring member may be utilized as well. Thistoggle ring member 14 is generally oriented diagonally relative to alongitudinal axis 15 of the tubular anchor body 12. The toggle ringmember 14 thus formed remains connected to the main portion of thetubular body 12 by two thin struts 16 which are situated such that theyare substantially orthogonal to the orientation of the toggle ringmember 14, and disposed at an acute angle θ relative to the longitudinalaxis 15 (FIG. 2 a).

It is preferred that the anchor 10 be fabricated of biocompatiblematerials such as 300-series stainless steel (Type 304 or Type 316, forexample) or titanium, although suitable bioresorbable plastics maypotentially be used as well.

FIGS. 2 a and 2 b are cross-sectional views of the bone anchor 10 in itsundeployed and deployed states, respectively. FIG. 2 a illustrates moreclearly how the struts 16 connect the tubular body 12 to the toggle ringmember 14. As can be seen in FIG. 2 b, which illustrates the bone anchorin its deployed state, the struts 16 are designed so that they willreadily bend or deform to an orientation which is substantiallyorthogonal (transverse) to the axis 15 when a force 17 is applieddistally to the toggle ring member 14 and/or a force 18 is appliedproximally to the tubular body 12. As the thin struts 16 bend responsiveto the forces applied to the tubular body 12 and/or the toggle ringmember 14, the toggle ring member is compressed against the tubularanchor body 12 until it is in a fully deployed transverse positionrelative to the anchor body 12 and the struts 16 are disposed in arelatively flat transverse orientation between the anchor body 12 andthe deployed toggle ring member 14. The transverse orientation of thetoggle ring member 14 relative to the anchor body 12 allows the togglering member 14 to present an effective anchoring profile to the corticalbone surface when the bone anchor apparatus 10 is deployed, as shall bemore fully illustrated in the subsequent figures. Referring now to FIG.3, a hollow casing 19 has been inserted into the bone anchor 10, andattached to the anchor body 12 utilizing methods well known in the art,such as crimping, welding or the like, in order to secure the boneanchor 10 to the casing 19. In the embodiment shown herein asubstantially flat tongue 20 (see also FIG. 5) formed at the distal endof the casing 19, has been inserted into a slot 22 in the outer sidewallof the anchor body 12, and then welded at weldment 23 (FIG. 5) onto theoutside surface of the anchor body 12. The casing 19 is attached to thebone anchor 10 to provide a means for inserting the bone anchorapparatus into the surgical area arthroscopically. The casing 19 ispreferably of a hollow tubular shape at its proximal end 24 andpreferably has a half-cylindrical shape at its distal end 26. This halfcylindrical shape allows a length of suture 28 which has been threadedor stitched through desired soft tissue, such as a tendon, to be passedthrough the casing 19 and into the tubular body 12 through its openproximal end 13. The length of the suture 28 then preferably extendsdistally though the axial length of a lumen 29 of the body 12 and thenaround a suture return pin or pulley 30 at a distal end 31 of the body12. The pin 30 may be fixedly secured within the body 12, or mayalternatively be journaled to permit rotation. A further alternativeapproach is to secure the pin to the body 12 so that it may moveaxially. The suture returns through the lumen 29 in a proximaldirection, exiting the body 12 from its proximal end 13 and thentraversing the interior lumen of the hollow casing 19, exiting thehollow casing 19 from its proximal end 32 such that the free ends 33 ofthe suture 28 may be handled by the medical practitioner performing thesubject procedure. Referring still to FIG. 3, in the illustratedembodiment, a hollow mandrel 34 is placed over the proximal end of thecasing 19, in coaxial fashion, such that it may be moved in a distaldirection until it comes into contact with the toggle ring member 14connected to the proximal end of the body 12, thereby deploying suchtoggle ring member 14 as shall be shown in the following figures.

It should be noted, at this juncture, that, while a presently preferredmeans for securing the suture 28 to the bone anchor 10 has beenillustrated, any other suitable means for securing suture to boneanchors known in the art may be utilized in combination with theinventive bone anchor 10. For example, the suture 28 may merely beknotted to a provided eyelet on the body 12, or through a suturereceiving aperture or apertures on the anchor 10. Another alternativecould be to wrap the suture about a portion of the anchor 10 to secureit thereto.

Referring now in particular to FIGS. 4-6, the manner in which the boneanchor 10 is deployed into desired bone structure to secure soft tissueto bone will be described. In FIG. 4, there is shown a cross-sectionalview of a human shoulder 38 on the left side of the body as seen fromthe front of the body and which illustrates a rotator cuff tendon 40which is disposed across a humeral head 42. This illustration isintended only to provide a simple structural overview of thephysiological elements involved in a typical situation involving therepair of a patient's rotator cuff, where it is to be desired that therotator cuff tendon 40 be reattached to a humeral head 42. It should benoted, of course, that the invention is applicable to many other typesof orthopedic repairs which involve the attachment of soft tissue toadjacent bone structure.

It is to be understood that, in this illustration, the rotator cufftendon 40 is not attached to the humeral head 42 at the interface 44between the two, as is typically the case when a patient's rotator cuffhas become damaged due to injury or overuse, and requires repair. Thehumeral head 42 is comprised of an outer surface of cortical bone 46 andinner cancellous bone 48. A trocar 50 has been inserted into theshoulder 38 in proximity to the area where the rotator cuff tendon 40 isto be reattached to the humeral head 42, to allow for arthroscopicaccess, and a hole 52 has been made, preferably by drilling or punching,in the desired location through the cortical bone 46 and into thecancellous bone 48. A suture 28, is stitched in a suitable manner to therotator cuff tendon 40 which is to be secured to the humeral head 42.The stitching process may be accomplished by any known means, and anyknown suture stitch may be employed, the objective being to ensure asecure stitch so that the suture is not inadvertently separated from thetendon after completion of the repair procedure, necessitating re-entryto the surgical site. In preferred approaches, the suture is attached tothe soft tissue using a “mattress stitch”, which is well known in theart as being a particularly secure stitch which is unlikely to failpostoperatively. Preferably, a suturing instrument is inserted into thetrocar to perform the aforementioned suturing step. A preferred suturingapproach is taught in co-pending application Ser. No. 09/668,055,entitled Linear Suturing Apparatus And Methods, filed on Sep. 21, 2000,expressly incorporated herein by reference and commonly assignedherewith. Of course, the inventive devices may also be utilized in anopen surgical procedure, if desired, wherein the sutures are manuallyplaced. Once the suturing process is completed, the free ends 33 of thesuture 28 are removed proximally through the trocar from the patient'sbody, together with the suturing instrument.

As shown particularly in FIG. 5, the free ends 33 of the suture 28,while still outside of the patient's body, are then passed distallythrough the toggle ring member 14 and the casing 19, into the body 12,around the suture return pin 30, and then proximally out of the body 12and casing 19 where the free ends 33 may be manipulated by the surgeon.In FIG. 5, the anchor apparatus 10 is still in its undeployed state. Themandrel 34 has been inserted over the casing 19 such that it is disposedadjacent to the proximal end of the toggle ring member 14 prior todeployment. In the presently preferred method, the entire apparatus 10,including the body 12, the casing 19, and the mandrel 34, once loadedwith the suture 28, is then inserted through the trocar 50 and into thehole 52 in the humeral head 42 illustrated in FIG. 4.

FIG. 6 illustrates how the bone anchor is deployed after it has beeninserted into the hole 52 in the humeral head 42. The entire apparatusis inserted into the hole 52 a sufficient distance so that the togglering member 14 is disposed just distally of the juncture between thecortical bone 46 and the cancellous bone 48, just within the cancellousbone 48. Once so positioned, the bone anchor 10 may be deployed withinthe cancellous bone 48 to lock the anchor 10 into position, therebysecurely attaching the suture 28 to the humeral head 42. To deploy theanchor 10, in a preferred method, the casing 19 is withdrawn proximally.Because of its connection through joint formed between the tongue 20 andslot 22, this withdrawal force applied to the casing 19 will also causethe body 12 to move in a proximal direction until it engages the distalside of the toggle ring member 14. Preferably, the mandrel 34 ismaintained in a stationary position, so that the continued proximalmovement of the body 12 against the toggle ring member 14 results in theapplication of sufficient force on the struts 16 to cause them todeform, thereby decreasing the axial spacing between the toggle ringmember 14 and the proximal end of the body 12 to a relatively smalldistance. Referring again to FIGS. 2 a and 2 b, this force appliedagainst the toggle ring member 14 and struts 16 also cause the togglering member 14 to move in a pivoting fashion from an undeployedorientation, wherein the ring member 14 is disposed at an acute angle θrelative to the longitudinal axis 15 (FIG. 2 a) to present a smallerprofile in a direction transverse to the axis 15, to a deployedorientation, wherein the ring member 14 is disposed substantiallytransversely to the axis 15 (FIG. 2 b) in order to present a largerprofile in a direction transverse to the axis 15. This deployment of thetoggle ring member and consequent increase in the transverse profile ofthe toggle ring member 14, causes the ends of the toggle ring member 14to push or dig into the soft cancellous bone just beneath the surface ofthe cortical bone layer 46. Because the profile of the toggle ringmember 14 in its deployed state is larger than the diameter of the hole52, the apparatus is prevented from being pulled proximally out of thehole 52 after it has been deployed. The surface area of the toggle ringmember 14 which is in contact with the cancellous bone 48 also preventsthe apparatus from being moved either distally or laterally afterdeployment.

As noted supra, it is preferable to maintain the mandrel 34 in astationary position, while moving the body 12 proximally to applydeployment force against the toggle ring member 14. The reason for thisis that by holding the mandrel 34 steady, the practitioner canaccurately control the depth at which the anchor 10 is deployed, so thatthe toggle ring member is deployed just distally of the distal surfaceof the cortical bone 46. If, instead, the mandrel were moved distally toapply force against the toggle ring member 14, ascertainment of thedepth of the deployed toggle ring member would be more difficult.However, if desired, the mandrel 34 may be moved distally against thetoggle ring member 14 while the casing 19 is maintained in a stationaryposition, thereby pushing the toggle ring member 14 distally until theresultant forces on the struts 16 cause them to deform. Still anotheralternative is to move the mandrel 34 distally, while at the same timemoving the body 12 proximally, to apply both a proximally directed and adistally directed force against the toggle ring member 14 and associatedstruts 16.

Ideally, as noted supra, once the toggle ring member or arm 14 has beenfully deployed, it will have rotated to an orientation fully transverse(90 degrees displaced from) the axis 15. In such an orientation, thefuture loads on the arm 14, caused by axial forces applied to the anchor10 during usage of the shoulder (i.e. during rehabilitation therapy),will be columnar, and will thus not pose a substantial risk of cyclicloading on the arm, with its attendant risk of eventual failure.However, in actual cases, it is unlikely that the arm 14 will always beoriented at precisely a 90 degree angle to the axis 15, and it istherefore undoubtedly the case that the struts 16 will see some degreeof cyclic rotational loading during the healing process. Thus,Applicants have determined that arm 14 and struts 16 should preferablybe annealed during the manufacturing process, to soften the materialfrom which they are formed, thereby making the struts more ductile, sothat they can tolerate such loading without failing.

Referring still to FIG. 6, the manner in which the casing 19 and mandrel34 are removed from the procedural site after deployment of the boneanchor 10 is illustrated. Once the toggle ring member 14 is firmlypositioned in the cancellous bone 48 just below the cortical bonesurface 46, the casing 19 is withdrawn in a proximal direction. Thetongue 20 which is inserted through the slot 22 in the distal end 26 ofthe casing 19 is designed to break upon the application of a withdrawalforce of a predetermined strength on the casing 19, which force isconsiderably less than the force necessary to pull the deployed boneanchor 10 out of the hole 52. As a result, the bone anchor 10 remainsfirmly in place while the casing 19 and the mandrel 34 are removedthrough the trocar and out of the body.

FIG. 7 provides an overall view of the shoulder area and the bone anchorapparatus after the bone anchor 10 has been deployed into the hole 52 inthe humeral head 42 and as the casing 19 and mandrel 34 are beingremoved through the trocar 50. After the casing 19 and mandrel 34 areremoved from the procedural site, the free ends 33 of the suture 28still extend through the trocar 50 and out of the body. The surgeon maythen cinch and knot the free ends of the suture 28 to secure the suture28 to the bone anchor 10, and to snug the tendon 40 to the humeral head42, as desired, or may employ a separate suture-securing device. Manydifferent methods or devices may be employed to attach the suture 28 tothe bone anchor device 10 or to a separate suture securing device andthese means will be well known to those of ordinary skill in the art.The precise means of securing the suture 28 is beyond the scope of thisdescription.

FIG. 8 illustrates an alternative embodiment of the present invention. Abone anchor 110 is shown which is similar to the bone anchor describedin connection with the above illustrations. It comprises a tubular orcylindrical body 112 and a toggle ring member 114. The only significantdifference in this alternative embodiment is the absence of the thinstruts 16 shown in the prior figures. In this alternative embodiment thetoggle ring member 114 is hinged directly to the anchor body 112. It isdeployed in the same manner using a casing and a mandrel as describedabove, but in this embodiment the toggle ring member 114 simply bends atthe hinge point 116 to move from its undeployed position (illustrated inFIG. 8) in relation to the anchor body 110 to its deployed position (notshown, but similar to the deployed position of the first embodimentillustrated in FIG. 2 b).

Additional alternative embodiments of the present invention may be seenby referring to FIGS. 9 a-c. FIG. 9 a shows an embodiment consisting ofa substantially rectangular anchor 210 having a solid anchor body 212and a solid rectangular member 214 attached by means of a hinge 216 fordeployment into the bone structure below the cortical surface. Ratherthan using a casing that is inserted into the anchor body as in theembodiments described above, the rectangular member 214 is deployed bymeans of a mandrel 218 which pushes a first end of the rectangularmember 214 distally at the same time that a rod 220 attached to theopposing end of the rectangular member 214 pulls that end proximally,thereby deploying the member 214 to an orientation having a greatertransverse profile, as in the prior embodiments. The rod 220 is designedsuch that it will break away from the rectangular member 214 when aproximal force is exerted on it after deployment of the rectangularmember 214 so that the rod 220 and the mandrel may be removed.

The alternative embodiment shown in FIG. 9 b is deployed in exactly thesame manner as the embodiment shown in FIG. 9 a. The only differencebetween the two embodiments is the configuration of the anchor 310,which has a tubular body 312 and a tubular toggle ring deployment member314.

FIG. 9 c shows yet another alternative embodiment of a bone anchor 410with a hollow tubular body 412, and a hollow toggle ring deploymentmember 414 similar to the embodiment described above, supra, but whichis deployed by means of a mandrel 418 and rod 420 as with thealternative embodiments described in connection with FIGS. 9 a and 9 b.

In FIGS. 10A through 20B are illustrated a preferred embodiment whichincludes a presently preferred suture anchoring approach. FIGS. 10A-10Band 11A-11D are cross-sectional views through the left shoulder of ahuman as viewed from the front and illustrate the use of an exemplarysuture anchor system 520 for repairing a rotator cuff tendon injury. Therotator cuff tendon 522 is shown in its natural positioned overlying thebulbous humeral head 524 of the humerus bone 526. In rotator cuffinjuries, the tendon 522 partially or completely separates from itsattachment point to the humeral head 524, which point of attachment istypically located along an angled shelf, the greater tuberosity 528. Inminimally invasive surgeries to repair the rotator cuff injury, thesurgeon threads one or more sutures through the rotator cuff tendon 522and anchors them to the greater tuberosity 528. The suture anchor system520 of the present invention facilitates this latter step of anchoringthe sutures to the greater tuberosity 528.

With reference first to FIG. 10A, a generally tubular trocar 530provides a conduit through the soft tissue of the shoulder for thesuture anchor system 520 of the present invention. Typically, thesurgeon makes an incision or stab wound through the outer dermal layersof sufficient size to permit passage of the trocar 530 through skin andthe deltoid muscle into proximity with the humeral head 524. Varioustrocars and techniques for creating the approach passageway are knownand may be utilized with the present invention. In addition, more thanone incision and conduit may be necessary to perform the severalsuturing and anchoring steps.

After establishing one or more direct conduits to the humeral head 524,the surgeon passes a length of suture through the soft tissue of therotator cuff tendon 522 so that a loop 532 of suture material isembedded therein, as seen in FIG. 10B. The two free ends 534 a, 534 b ofthe length of suture are withdrawn from the patient and coupled to thesuture anchor system 520. The specifics of this coupling and subsequentmanipulation of the two free ends of the suture will be described morefully below. For the purpose of explaining the exemplary method of use,it is sufficient to understand that the two free ends 534 a, 534 b passinto a lumen at the distal end of the suture anchor system 520 andextend through the lumen in a proximal direction to a proximal end ofthe system to enable fixation or pulling of the suture ends. As seen inFIG. 10B, the two free ends 534 a, 534 b are shown projecting from aproximal end of the system. The system 520 further includes a pluralityof concentrically disposed cannulas or tubes as shown that perform theknotless suture anchoring operation. The interrelationship andfunctioning of these tubes will also be more fully explained below.

The exemplary system 520 as illustrated is particularly suitable foranchoring a suture to a body cavity, specifically the humeral head 524as shown. When anchoring sutures to such a bone structure, aconventional technique is to first form a blind hole or cavity 540through the cortical layer 542 and into the soft cancellous matter 544,as seen in FIGS. 10A-10B and 11A-11D. The surgeon then positions asuture anchor 546 within the cavity 540 and deploys it such that itcannot be removed from the cavity.

The suture anchor 546 performs two functions: anchoring itself withinthe body cavity and anchoring the sutures therein. In the illustratedembodiment, the former function is accomplished using an expandableanchoring structure 548 located on the proximal end of the suture anchor546. The anchoring structure 548 is preferably the toggle ring 14illustrated in FIGS. 1-7, and functions like a toggle bolt used inceiling fixtures, specifically expanding to a larger dimension in thecavity 540 beyond the hard cortical bone 542. In this manner, the sutureanchor 546 is prevented from being removed from the cavity 540 once theanchoring structure 548 is deployed. Although the present inventionillustrates a particular anchoring structure 548, which is similar tothe afore-described toggle ring 14, it should be noted that any similarexpedient will work. For example, a different toggle-like anchoringstructure may be used such as shown in co-pending application Ser. No.09/616,802, filed Jul. 14, 2000, the disclosure of which is herebyexpressly incorporated by reference. Alternatively, an anchoringstructure that expands into contact with the cancellous matter 544 maybe used.

The second function of the suture anchor 546 is the anchoring orfixation of the suture with respect to the suture anchor itself, withoutthe use of knots. Desirably, the particular manner of anchoring thesuture with respect to the suture anchor 546 permits easy adjustment ofthe length of suture between the suture anchor and the loop 532 formedin the soft tissue. This adjustment allows the surgeon to establish theproper tension in the length of suture for effective repair of the softtissue; reattachment of the rotator cuff tendon 522 in the illustratedembodiment. In this regard, FIG. 11D shows the fully deployed sutureanchor 546 after the free ends 534 a, 534 b have been placed in tensionand locked within the suture anchor. Although not shown, the remainingsteps in the procedure involve withdrawing the concentric tubes from thesurgical site and severing the free ends 534 a, 534 b close to thesuture anchor 546.

FIGS. 12A-12C are different partial longitudinal sectional views takenthrough the exemplary suture anchor system 520 of the present invention.The suture anchor 546 is seen in cross-section disposed in aclose-fitting relationship within a delivery tube 550. The delivery tube550, in turn, may be arranged to slide within a larger tube 552,sometimes known as an introducer tube, that includes a valve (not shown)on a proximal end to prevent fluid leakage therefrom. Alternatively,such a fluid leakage valve may be provided on the proximal end of thetrocar 530 seen in FIGS. 10A-10B.

The suture anchor 546 is defined by a generally tubular anchor body 554and an inner deployment tube 556 fits closely within a proximal end andis fastened therein. The exemplary suture anchor 546 is shown anddescribed in greater detail below with respect to FIGS. 13A-14. Thedeployment tube 556 can also be seen on the right side in FIG. 12Aprojecting from the series of concentric tubes, with the free ends 534a, 534 b of the length of suture projecting therefrom. A die tube 558sized intermediate the delivery tube 550 and the deployment tube 556 isarranged for longitudinal displacement over the deployment tube 556. Inthe illustrated state of the system 520, the suture anchor 546 isundeployed within the delivery tube 550 and the die tube 558 ispositioned just proximal to the expandable anchoring structure 548. Afurther component of the suture anchor system 520 is a suture lockingplug 562 having an actuation rod 564 removably attached to a proximalend thereof and extending proximally within the deployment tube 556.

FIGS. 12A-12C all show the suture loop 532 extending transversely fromwithin the concentric tubes of the suture anchor system 520. In thisregard, the delivery tube 550 is provided with an axial slot 565, thedeployment tube 556 is provided with an axial slot 566, and the die tube558 has an axial slot 567. The free ends 534 a, 534 b of the length ofsuture pass through these aligned axial slots 565, 566, 567 to theinterior of the deployment tube 556 that opens into the lumen 568 of thetubular body 554. The aligned axial slots 565, 566, 567 permit passageof the free ends 534 a, 534 b into the system 520 from a location midwayalong the concentric tubes, as indicated in FIGS. 10A-11D.

The various described components of the suture anchor system 520 arerelatively axially movable to deploy the suture anchor 546. Variousmeans are known to relatively displace concentric tubes a predetermineddistance and/or with a predetermined displacement force. For example,the concentric tubes may extend out of the trocar 530 to an actuationdevice in the form of concentric syringe bodies/finger tabs.Alternatively, the concentric tubes may be attached to relativelymovable parts in a gun-type handle, and actuated by triggers or othersuch levers. It is to be understood therefore that the present inventionis not limited by the particular actuation device on its proximal end,and no further description in this regard will be provided.

A more complete understanding of the exemplary suture anchor 546 will behelpful prior to a detailed description of the structure and function ofthe concentric tubes to deploy the system. In this regard, FIGS. 13A-15illustrate one embodiment of a suture anchor 546 isolated from theremainder of the system and having the aforementioned tubular anchorbody 554 and deployable anchoring structure 548. The anchor body 554defines a lumen 568 therewithin. FIGS. 13A and 13B also illustrate thesuture locking plug 562 and attached actuation rod 564.

The anchor body 554 has the anchoring structure 548 on its proximal endand a suture pulley or suture return member 570 disposed in proximity toits distal end. The aforementioned suture loop 532 is schematicallyillustrated out of the soft tissue for clarity, and it should beunderstood that this suture loop 532 is embedded in the soft tissue inactual use of the system. The free ends 534 a, 534 b of the length ofsuture pass through an angled toggle ring 572 of the anchoring structure548 and into an open proximal end 574 of the lumen 568 formed within thetubular anchor body 554. The angled toggle ring 572 attaches to theproximal end 574 via a pair of plastically deformable struts 576. Boththe toggle ring 572 and struts 576 are initially formed as a projectionof the tubular anchor body 554. After continuing in the distal directionthrough the lumen of the anchor body 554, the free ends 534 a, 534 bwrap around the suture return member 570 and traverse the lumen in theproximal direction to emerge from the angled toggle ring 572 as shown.

As best seen in FIG. 13B, the actuation rod 564 extends into an opendistal mouth 576 of the anchor body 554 and through the lumen 568 andangled toggle ring 572. The actuation rod 564 and four strands of thelength of suture thus share the space within the lumen 568. Because ofthe relatively smaller size of the actuation rod 564 with respect to thelumen 568, the length of suture may slide axially within the lumenwithout interference. It can therefore be seen that because the sutureloop 532 is embedded in soft tissue, pulling on the free ends 534, 534 bof the length of suture places the suture loop in tension.

Prior to a more exhaustive description of the function of the lockingplug 562 to perform the second function of the suture anchor 546 (i.e.,anchoring the length of suture with respect to the suture body 554), useof the concentric tubes to deploy the anchoring structure 548 will beexplained. With reference again to FIGS. 12A-12C, the deployment tube556 can be seen attached within the lumen 568 of the anchor body 554using a tab 580. Of course, other means for attaching the deploymenttube 556 within the lumen of a body 554 may be provided, but a small tab580 bent inwardly from the anchor body 554 and welded or otherwisesecured to the deployment tube 556 is a suitable expedient. The tab 580is desirably provided at only one location around the circumferentialjunction between the deployment tube 556 and lumen 568 to facilitatesevering of this connection, although more than one attachment may beprovided. The tab 580 thus secures the deployment tube 556 within theanchor body 554 of the suture anchor 546, while both the die tube 558and actuation rod 564 can freely slide with respect to the anchor body554.

After positioning the delivery tube 550 in proximity with the preformedbody cavity 540 as seen in FIGS. 10A and 10B, the surgeon advances thedeployment tube 556 having the suture anchor 546 attached thereto intothe cavity. The suture locking plug 562 and die tube 558 advance alongwith the deployment tube 556, and the resulting configuration is seen inFIG. 10B.

Using a depth measurement, or visualization technique, the surgeoninsures that the suture anchor 546, and in particular the anchoringstructure 548, has been inserted past the hard outer layer of corticalbone 542. The anchoring structure is then expanded as seen in FIG. 11A.To accomplish this, the die tube 558 contacts the angled toggle ring 572and forces it into an orientation that is generally perpendicular withrespect to the axis of the suture anchor 546. With reference to FIGS.12A-12C, the die tube 558 is desirably held stationary while thedeployment tube 556 having the suture anchor 546 attached thereto ispulled in a proximal direction. Again, the relative movement of thesetubes can be accomplished using a handle or other device exterior to thepatient's body. Pulling on the deployment tube 556 forces one side ofthe angled toggle ring 572 against the generally circular distal mouthof the deployment tube 556 which deforms the struts 576 as the togglering 572 moves into a perpendicular orientation.

After the anchoring structure 548 is deployed, further pulling on thedeployment tube 556 detaches it from the suture anchor 546.Specifically, the aforementioned welded tab 580 severs at apredetermined pulling force. The die tube 558 remains in place in itsfixed position, and provides a reaction force against the suture anchor546. The deployment tube 556 is then pulled free and retracted out ofthe way, as indicated in FIG. 11B. At this stage, the suture anchor 546is secured with respect to the body cavity, but the length of suturepassing therethrough remains free to be axially displaced.

Now with specific reference to FIGS. 12A-12C, the path of the length ofsuture through the suture anchor system 520 will be described. Thesuture loop 532 is seen projecting upward from the system, but it againshould be noted that this loop is embedded in soft tissue in use of thesystem. The two free ends 534 a, 534 b extend through an axial slot 590in the delivery tube 550, and through an axial slot 590 in thedeployment tube 556 into lumen 568 of the suture can 546. As best seenin FIG. 12C, the free ends pass through the lumen 568 and around theaforementioned suture return member 570. The free ends then travel in aproximal direction through the lumen 568 and through the lumen of thedeployment tube 556 to emerge from proximal end of the system. Becausethe suture loop 532 is embedded in soft tissue, pulling on both of thefree ends 534 a, 534 b, or pulling on one end while holding one fixed,will create tension in the length of suture. The suture return member570 provides relatively little resistance to sliding of the length ofsuture therearound, and thus this tensioning can be accomplishedrelatively easily.

In one embodiment, the suture return member 570 comprises a pin orientedtransversely to the axis of the suture anchor 546 and located along asidewall thereof. As seen best in FIG. 13A, the pin may span an axialslot 600 in a sidewall of the anchor body 554 so that the free ends 534a, 534 b of length of suture can pass out through the slot and aroundthe pin. Alternatively, two axially spaced holes with chamfered orrounded edges may be formed in the sidewall of the anchor body 554through which the free ends 534 a, 534 b can be threaded and fixed. Ofcourse, numerous structures are contemplated that provide the functionof the illustrated pin-type suture return member 570. Moreover, insteadof being a fixed structure, the suture return member 570 can be arrangedto swivel or otherwise move to facilitate sliding motion of the freeends 534 a, 534 b therearound. In a specific example, the pin-typesuture return member 570 can be formed separately from the anchor body554 and inserted within a pair of facing holes in the edges of the slot600. In this manner, the pin-type suture return member 570 rotateswithin the holes, thus reducing friction between the free ends 534 a,534 b and the suture return member.

The step of tensioning the length of suture is seen in FIG. 11C, whereinthe suture locking plug 562 remains in its initial position spaced fromthe anchor body 554. Adjustment of the length of the suture between thesuture anchor 546 and the loop 532 is very important to ensure properfixation of the rotator cuff tendon 522 with respect to the humeral head524. If the suture is pulled too tightly, the rotator cuff tendon 522may be unduly stressed, and the loop 532 may even pulled free from thetendon. On the other hand, if the suture is too loose, the goal ofreattaching the tendon 522 in its proper location will be compromised.

Once the surgeon has established proper tension on the suture, thesuture is anchored with suspect to the anchor body 554. This is done bydisplacing the suture locking plug 562 in a proximal direction so thatit is forced into the lumen 568. The plug 562 includes a generallycylindrical shaft 602 with a bullet-shaped proximal nose 604 to helpprevent its catching on a distal mouth 605 of the anchor body 54.Proximal displacement of the actuation rod 564 from outside the bodycauses proximal movement of the attached plug 562.

FIGS. 16A-17C show the anchor body 554 without the aforementionedanchoring structure 548, for clarity. These views illustrate themovement of the suture locking plug 562 into the lumen 566, andconsequent locking of the length of suture therein. The diameter of thecylindrical shaft 602 of the plug 562 is sized to be slightly smallerthan the inner diameter of the lumen 568. As seen in FIGS. 17B and 17C,the diameter of the cylindrical shaft 602 is such that it compresses thefour strands of the length of suture against the lumen 568. The lockingplug 562 is dimensioned to compress or “crush” the length of suture inthe lumen 568 and interfere with its axial movement therethrough. Theamount of compression may be measured by the amount of pull force on thesuture necessary to move it once the plug is in position. Desirably, thepull force is in a range that would exceed the USP (United StatesPharmacopeia) Standard knot pull strength (USP 24) of the suture used.In the specific case of #2 braided polyester suture, this knot pullstrength is approximately 3.5 Kgf. In practice, however, the knot pullstrength of commercially available #2 braided polyester suturesapproaches 14 Kgf.

Proximal displacement of the locking plug 562 within the anchor body 554is desirably limited by a positive stop. In the illustrated embodiment,a stop flange 610 projects outwardly from the cylindrical shaft 602 atits distal end. The stop flange 610 slides within an axial slot 612 atthe distal end of the anchor body 554 that terminates at a slot end 614.Although not shown in the figures, proximal movement of the locking plug562 is ultimately restricted by contact between the stop flange 610 andthe slot end 614. Of course, other configurations that provide apositive stop to proximal movement of the locking plug 562 arecontemplated. For example, rather than dimensioning the locking plug 562to be larger than the lumen 568 of the anchor body 554 (as exhibited bythe stop flange 610), a stop surface may project inwardly from the lumen568 to interfere with movement of the plug 562.

One advantage provided by the present invention is the ability totighten a suture loop embedded within soft tissue to a predeterminedtension, and then locked to the suture within a suture anchor withouteven slightly altering that tension. As best seen in FIG. 17B, thelocking plug 562 is shown partly inserted within the tubular body 554during the step of being pulled proximal by the actuation rod 564 asindicated by the movement arrows 616. The free ends 534 a, 534 b of thelength of suture extend around the suture return member 570, havingpreviously been tensioned to a predetermined amount. Proximal movementof the locking plug 562 acts on all four strands of the length of suturewithin the lumen of the tubular body 554, and thus imparts equalfrictional forces to all of the strands tending to urge them in aproximal direction. Because the four strands loop around the suturereturn member 570, with two coming and two going, these frictionalforces cancel out such that the free ends 534 a, 534 b do not migratewithin the tubular body 554. Because the suture return member 570 andtubular body 554 remain fixed with respect to the suture loop 532 (whichis embedded within the soft tissue), the predetermined tension withinthe loop remains constant during the suture locking step.

In a further example, as seen in FIGS. 18A and 18B, deformation of theangled toggle ring 572 forces it into an oval shape at the proximal end574 of the anchor body 554. This oval shape may have a minor dimensionthat is smaller than the diameter of the cylindrical shaft 602, or moretypically the struts 576 may be bent into the path of the shaft 602,thus presenting an interference and a positive stop to the shaftmovement. Alternatively, the actuation rod 564 may be bent back upon theexterior surface of the locking plug 562 to form the stop surface.

Once the suture locking plug 562 has been positively stopped, theactuation rod 564 may be detached therefrom. As seen in the figures, theactuation rod 564 extends within a through bore in the cylindrical shaft602 and includes a frangible point 620 in that bore. The segment of theactuation rod distal to this frangible point 620 is secured within thebore in a conventional manner, such as with crimping indicated at 622 inFIG. 16A. The die tube 558 may be used as a reaction force against theanchor body 554 while the actuation rod 564 is pulled in the proximaldirection, causing the frangible point 620 to fracture. The finalconfiguration is seen in FIG. 11D.

As mentioned above, the exemplary structure for locking sutures relativeto a body cavity may be utilized in a variety of anatomicalenvironments. For instance, FIG. 19 shows an alternative surgicaltechnique for using a combined suture anchor 546′ and anchoringstructure 548′ to repair a rotator cuff tendon 522. In this embodiment,rather than forming a blind cavity within the humeral head 524, thesurgeon forms a cavity 630 that transects the greater tuberosity 528 andopens through the cortical layer 542 at both ends. After embedding theloop 532 of suture material within the rotator cuff tendon 522, the freeends 534 a, 534 b are inserted into and threaded through the cavity 630.The ends 534 a, 534 b are then passed through the lumen formed withinthe combined suture anchor 546′ and anchoring structure 548′, whichcombination is then inserted as shown into the cavity 630. The free ends534 a, 534 b of suture are then tightened to the prescribed level andsecured within the suture anchor 546′. It should be noted that thecombined suture anchor 546′ and anchoring structure 548′ may beconfigured somewhat differently to permit the aforementioned tighteningstep, though the suture locking steps are preferably accomplished in thesame manner as described above; namely, with a suture locking plugcompressing the length of suture within the suture anchor 546′.Furthermore, the anchoring structure 548′ contacts the exterior of thecortical bone rather than the interior as described above.

FIGS. 20A and 20B illustrate an alternative suture anchor 640 of thepresent invention having a body cavity anchoring structure 642 on aproximal end. A length of suture is shown having a loop 644 and a pairof free ends 646 a, 646 b passing through the anchoring structure 642and through a lumen 648 of a generally tubular body 650 of the sutureanchor 640. In a distal portion of the tubular body 650, the free ends646 a, 646 b pass out of the lumen 648 through a first aperture 652 aand re-enter the lumen through a second aperture 652 b located distallyfrom the first aperture. As illustrated, the lumen 648 in the region ofthe apertures 652 a, 652 b is only partly defined by a semi-cylindricalextension of the tubular body 650, but other arrangements having a morecomplete lumen at this location are within the scope of the presentinvention.

With reference to FIG. 20B, the apertures 652 a, 652 b are shown to berounded to reduce abrasion on the suture free ends 646 a, 646 b. Inaddition, the bridge portion 654 of the tubular body 650 that separatesthe apertures 652 a, 652 b defines a suture return member structure,much like the suture return member 570 (FIG. 17B) described above in theearlier embodiment. That is, the suture free ends 646 a, 646 b caneasily slide with respect to the bridge portion 654, especially becauseof the rounded corners, to permit tightening of the suture loop 644prior to locking the length of suture within the tubular body 650. Thelength of suture may be locked within the tubular body 650 using alocking plug as described above, or with another similar expedient.

It is to be understood that the figures of the bone and anchors seenabove are purely illustrative in nature, and are not intended toperfectly reproduce the physiologic and anatomic nature of the humeralhead as expected to be seen in the human species, nor to limit theapplication of the inventive embodiments to repair of the rotator cuff.The invention is applicable to many different types of proceduresinvolving, in particular, the attachment of connective or soft tissue tobone. All of the terms used herein are descriptive rather than limiting,and many changes, modifications, and substitutions may be made by onehaving ordinary skill in the art without departing from the spirit andscope of the invention, which is to be limited only in accordance withthe following claims.

What is claimed is:
 1. A method for attaching soft tissue to bonecomprising: inserting a suture anchor into a bone tunnel, said sutureanchor being preloaded with a suture and comprising a proximal end, adistal end, and a longitudinal axis extending from said proximal end tosaid distal end, and a lumen extending at least partially along saidlongitudinal axis, said lumen having an open proximal end, said sutureanchor further comprising a bone affixing member disposed towards theproximal end of said suture anchor, the bone affixing member having anaperture wherein the suture is passed through the aperture along thelongitudinal axis and distally into the lumen; actuating said boneaffixing member from an undeployed position wherein said bone affixingmember has a smaller profile in a direction transverse to saidlongitudinal axis to a deployed position wherein said bone affixingmember has a larger profile in said direction transverse to saidlongitudinal axis, said bone affixing member having no structure fordirectly attaching suture material thereto; wherein during the actuatingstep, the lumen remains coaxial with the bone tunnel; tensioning saidsuture to approximate said tissue to a desired position; immobilizingsaid suture such that said soft tissue is attached and affixed to saidbone at said desired position; passing the suture through the softtissue so that a loop of suture is disposed in the soft tissue,resulting in two free ends; passing the two free ends of the suture intothe lumen of the suture anchor through the aperture; and looping the twofree ends of suture about a suture return member disposed in the sutureanchor whereby the two free ends of suture extend proximally from thelumen through the aperture.
 2. The method of claim 1, whereinimmobilizing the suture further comprises fastening the two free ends ofsuture with respect to the suture anchor without knots.
 3. The method ofclaim 1, wherein immobilizing the suture comprises compressively lockinga portion of the suture within the lumen of the suture anchor.
 4. Themethod of claim 3, wherein compressively locking the portion of thesuture within the lumen of the suture anchor comprises displacing alocking plug proximally into the lumen of the suture anchor.
 5. Themethod of claim 4, wherein displacing the locking plug proximallyfurther comprises actuating an elongate actuation rod disposedproximally of the locking plug.
 6. The method of claim 1, whereinactuating the bone affixing member further comprises deforming aconnecting portion joining the bone affixing member to a suture anchorbody.
 7. The method of claim 1, wherein the bone affixing membercomprises a toggle member.
 8. The method of claim 7, wherein the togglemember is annular.
 9. The method of claim 7, wherein the toggle membercomprises a ring.
 10. The method of claim 9, wherein the ring iselliptical.
 11. The method of claim 1, wherein the undeployed positioncomprises disposing the bone affixing member at an acute angle relativeto the longitudinal axis.
 12. The method of claim 1, wherein thedeployed position comprises disposing the bone affixing member in asubstantially transverse orientation relative to the lumen.
 13. Themethod of claim 1, wherein a transverse dimension of the bone affixingmember in the undeployed position is substantially the same or less thana transverse dimension of a suture anchor body.
 14. The method of claim13, wherein the transverse dimension of the bone affixing member in thedeployed position is substantially greater than the transverse dimensionof the suture anchor body.
 15. The method of claim 1, wherein loopingthe two free ends of suture about the suture return member furthercomprises rotating the suture return member relative to a suture anchorbody.
 16. The method of claim 1, wherein during actuation the suturepath through the aperture and lumen remains substantially coaxial withthe bone tunnel.